The project is concerned with natural variation in chromosomal architecture under conditions of asexual (parthenogenetic) and sexual reproduction. The material consists of naturally parthenogenetic species of insects, particularly the all-female species of Australian grasshopper Warramaba virgo and related bisexual species. Warramaba virgo is a species of hybrid origin which arose, some thousands of years ago, by crossing of two bisexual species 'P196' and 'P169'. The techniques employed will include C-banding and G-banding of karyotypes, tritiated thymidine autoradiography to study DNA replication patterns of different clones, and in situ hybridization techniques with cRNA. Much of the work will be carried out using 'synthetic virgo' individuals (i.e. laboratory hybrids between P196 and P169) and triploid hybrids between W. virgo and the bisexual species. Studies on meiosis will also be carried out.